This US-Egypt collaborative project is a comparative study between spring vents, groundwaters, and travertines in the Nubian Desert of northern Egypt and similar springs in the Rio Grande rift of New Mexico. The US team, lead by Dr. Karl Karlstrom at the University of New Mexico will establish a new collaboration with Egyptian scientist Dr. Moustafa Selmi at Suez Canal University in Egypt. This project provides the US team access to a new arid field site and will enable them to expand their study of the detrimental effects of deeply sourced fluids on groundwater quality. This collaborative project has direct societal relevance for the management of water resources in Egypt, the western US, and other arid regions where population growth places a strain on water resources.
Intellectual merit. The research team will map and sample travertine-depositing springs because they are the surface record of fault-controlled conduit systems that tend to partition aquifer basins. These springs are associated with the highest values of endogenic fluid components (high in salts, 3He/4He, CO2, and metals) and hence of importance for understanding the endogenic endmember involved in groundwater mixing. The travertine itself also provides a datable record, using precise uranium-series geochronology, of the paleohydrology of these important regions. Ongoing studies in the western US and Australia have provided important data in addressing public concerns about how to protect and manage perennial spring vents, and protect their delicately balanced ecosystems, which include endemic species and unique microbiology. The term "vents" is used in a very literal sense as the PIs' overarching model is that these systems are continental analogs to the black and white smokers found in oceanic rift environments.
Broader impacts. Support for this joint Egypt-U.S. venture will allow the team to extend and better test the model and to engage two graduate students in an international research experience. The US PIs will work together with the University of Suez Canal to help build Egyptian and international collaboration through two planned workshops to be held in Egypt and hosted by the University of Suez Canal. The work plan will follow methods of Crossey et al., 2006; 2009, to map and sample water and gas from many of the travertine-depositing springs in the Nubian Desert, analyze water chemistry to parse out CO2 sources and analyze gas chemistry (including noble gases) to evaluate percentages of mantle and deep crustal-derived fluids mixing into the groundwater system. This project has intrinsic scientific interest in terms of understanding links between tectonics and endogenic influences on groundwater quality. It has broader impacts in terms of management of groundwater supply, training of junior scientists, and international cooperation.
The scientific research for this project involved establishing new linkages between: 1) the hydrology of the Nubian aquifer system of the Western Desert of Egypt, 2) the past hydrology of this system that resulted in the so-called "green Sahara" intervals, and 3) potential tectonic effects of the Red Sea rift zone for understanding tectonics and hydrology. We investigated the water quality of artesian wells of the regionally important artesian Nubian aquifer using a variety of chemical tracers and found that its CO2-rich groundwaters contain significant inputs derived from diffuse mantle degassing into the aquifer. These deep inputs provide evidence for mantle-driven fluid ascent (along faults) into the aquifer that tend to degrade water quality. Travertines are found in numerous locations and these were found to record an episodic recurrence of green Sahara intervals that reflect past wetter times. We are testing the hypothesis that Egyptian travertines and CO2-rich groundwaters record a previously under-appreciated mantle-to-surface fluid interconnection that also has implications for many continental- scale aquifer systems such as the Great Artesian Basin of Australia and western U.S. Colorado Plateau aquifers. In terms of societal importance, the "deep time/deep fluids" focus of our research shows mixing of deeply sourced water components that degrade water quality. This realization may help provide new insights in terms of international water management. Groundwater resources such as in the Nubian system have evolved over millions of years and current (interglacial) recharge rates are much lower than during the past wetter times (green Sahara episodes). Long flow-path aquifers such as the Nubian system contain "fossil groundwater" such that modern groundwater exploitation is not sustainable under current recharge conditions. This aquifer also underlies several different countries (Egypt, Sudan, Libya) which all depend on it for their economic sustenance and future development. Increased demands on groundwater make it more important to understand and manage groundwater to sustain human populations as well as the ecosystems that depend on groundwater. Our study provides new water chemistry data that can help establish the present condition of springs and artesian groundwater systems and also adds data on travertines that can help provide information about past conditions. The combined data help characterize aspects of the Nubian system such as hydrochemical mixing along long low paths, fault-influenced flow systems, variable water quality in different regions, and temporal changes to the aquifer system. The broader impacts of our work, in addition to the water sustainability issues described above, include international collaboration and training of under-represented U.S. graduate students. This project was instigated by an Egyptian post-doctoral student who came to the U.S. for 2 months in 2011. This led to an expedition in January, 2012, to the western Desert of Egypt that involved the 2 U.S. PIs, 3 U.S. graduate students (all of Hispanic descent), 2 Egyptian early career scientists, and 1 Egyptian PhD student. The research trip successfully returned 13 copper tube samples (for noble gas analysis), each with accompanying water and microbiology samples, and about 60 travertine samples (for paleoclimate work). This trip was an ambitious reconnaissance sampling expedition to Kurkur, Kharga, Dakhla, and Farafra, and Bahariya Oases. All permits were arranged from Desert Arrow Tours who provided two 4-WD vehicles, two local drivers, and a multi-lingual tour guide. Travertine samples are now archived both at UNM and at South Valley University in Luxor and are available to other researcher upon request. Post-trip research activities have involved noble gas analyses done at the lab of Dr. Robert Poreda (Rochester), water chemistry analysis (major and trace elements) done at UNM, stable isotope analyses of waters and travertines done at UNM, and U-series dating of travertine done at UNM. We have presented several abstracts at national meetings and have two manuscripts in preparation: one on water chemistry and one on travertine chronology and paleohydrology of the Western Desert. This project has successfully established an international, multi-institutional collaboration involving UNM, western Michigan University (with Dr. Mohammed Sultan), University of Illinois, Chicago Circle (Dr. Neil Sturchio), Hamilton College (Dr. Barbara Tewksbury), University of Suez Canal (Dr. Mustafa Selmi), South Valley University of Aswan (Dr. Sayed Abdou Ahmed Selim), and South Valley University of Luxor (Abdel Mawgood Mohammed; presently at Western Michigan University but planning to return to Luxor). It is unclear if there will be next opportunities to continue our Egyptian field research, but establishing the personal contacts between U.S. and Egyptian researchers will hopefully have long-lasting positive benefits both scientifically and politically. In our expedition, we also made numerous personal contacts with Egyptian citizens that were cordial and friendly and likely had a positive impact on U.S.-Egyptian relations at the important level of individual citizens and scientists. Our UNM graduate students have benefitted from the expanded view that comes from international travel and international scientific collaboration.
